var myFocus = {
    $: function(id) { return document.getElementById(id); },
    $$: function(tag, obj) { return (typeof obj == 'object' ? obj : this.$(obj)).getElementsByTagName(tag); },
    style: function(obj, style) { return (+[1, ]) ? window.getComputedStyle(obj, null)[style] : obj.currentStyle[style]; }, //getStyle简化版
    easeOut: function(t, b, c, d) { return -c * ((t = t / d - 1) * t * t * t - 1) + b; },
    move: function(obj, prop, val, type, spd, fn) { //运动函数，spd为运动需要的时间，时间越大速度越小
        var t = 0,
            b = parseInt(this.style(obj, prop)),
            c = val - b,
            d = spd || 50,
            st = type,
            m = c > 0 ? 'ceil' : 'floor';
        if (obj[prop + 'Timer']) clearInterval(obj[prop + 'Timer']);
        obj[prop + 'Timer'] = setInterval(function() {
            if (t < d) { obj.style[prop] = Math[m](myFocus[st](++t, b, c, d)) + 'px'; } else {
                clearInterval(obj[prop + 'Timer']);
                fn && fn.call(obj);
            }
        }, 10);
        return this;
    },
    addList: function(obj, cla, x) { //生成HMTL,cla为列表的class,其中封装有:cla='txt'(生成alt文字),cla='num'(生成按钮数字),cla='thumb'(生成小图)
        var s = [],
            n = x || this.$$('li', this.$$('ul', obj)[0]).length,
            num = cla.length;
        for (var j = 0; j < num; j++) {
            s.push('<ul class=' + cla[j] + '>');
            for (var i = 0; i < n; i++) { s.push('<li>' + (cla[j] == 'num' ? (i + 1) : (cla[j] == 'txt' ? this.$$('li', obj)[i].innerHTML.replace(/\<img.*?\>/i, this.$$('img', obj)[i].alt) : (cla[j] == 'thumb' ? '<img src=' + (this.$$('img', obj)[i].getAttribute("thumb") || this.$$('img', obj)[i].src) + ' />' : ''))) + '<span></span></li>') };
            s.push('</ul>');
        };
        obj.innerHTML += s.join('');
    },
    setting: function(par) {
        if (window.attachEvent) { window.attachEvent('onload', function() { myFocus[par.style](par) }); }　　
        else { window.addEventListener('load', function() { myFocus[par.style](par) }, false); }
    },
    mF_liuzg: function(par) {
        var box = this.$(par.id),
            boxH = box.offsetHeight,
            t = par.time * 1000;
        this.addList(box, ['txt-bg', 'txt', 'num']);
        var pic = this.$$('li', this.$$('ul', box)[0]),
            n = pic.length;
        var c = boxH % par.chip ? 8 : par.chip,
            h = boxH / c,
            pics = [];
        for (var i = 0; i < c; i++) {
            pics.push('<li><p>')
            for (var j = 0; j < n; j++) pics.push(pic[j].innerHTML);
            pics.push('</p></li>')
        }
        this.$$('ul', box)[0].innerHTML = pics.join('');
        var ul = this.$$('ul', box),
            txt = this.$$('li', ul[2]),
            btn = this.$$('li', ul[3]),
            pic = this.$$('li', ul[0]);
        for (var i = 0; i < c; i++) { //初始化样式设置
            this.$$('p', pic[i])[0].style.top = -i * h + 'px';
            pic[i].style.height = h + 'px';
            this.$$('p', pic[i])[0].style.height = boxH * c + 'px';
        }
        var index = 0; //开始显示的序号
        box.removeChild(this.$$('div', box)[0]);
        var run = function(idx) {
            var tt = par.type == 4 ? Math.round(1 + (Math.random() * (3 - 1))) : par.type; //效果选择
            btn[index].className = '';
            txt[index].style.display = 'none';
            if (index == n - 1) index = -1;
            var N = idx != undefined ? idx : index + 1;
            var spd = tt == 2 ? 20 : (tt == 1 ? 80 : Math.round(20 + (Math.random() * (80 - 20))));
            for (var i = 0; i < c; i++) {
                if (tt == 3) spd = Math.round(20 + (Math.random() * (80 - 20)));
                myFocus.move(myFocus.$$('p', pic[i])[0], 'top', -N * c * h - i * h, 'easeOut', spd);
                spd = tt == 2 ? spd + 10 : (tt == 1 ? spd - 10 : spd);
            }
            btn[N].className = 'current';
            txt[N].style.display = 'block';
            index = N;
        }
        run(index);
        var auto = setInterval(function() { run() }, t);
        for (var j = 0; j < n; j++) {
            btn[j].j = j;
            btn[j].onclick = function() { if (!this.className) run(this.j) }
        }
        box.onmouseover = function() { clearInterval(auto); }
        box.onmouseout = function() { auto = setInterval(function() { run() }, t); }
        for (var i = 0, lk = this.$$('a', box), ln = lk.length; i < ln; i++) lk[i].onfocus = function() { this.blur(); } //去除虚线框
    }
};
myFocus.setting({
    style: 'mF_liuzg', //style为风格样式，
    id: 'myFocus', //焦点图ID
    chip: 8, //图片切片数量，能被焦点图的高整除才有效，默认为8片
    type: 2, //切片效果，1为甩头，2为甩尾，3为凌乱，4为随机效果
    time: 4 //每帧图片时间间隔
});